Cambridge biotech Genzyme has priced its new pill to treat Gaucher disease at $310,250 a year for the small population of US patients suffering from the rare genetic disorder.

The price — listed as $23,800 for a 28-day supply — is slightly higher than the $300,000 average annual cost of Genzyme’s flagship Gaucher treatment Cerezyme, a protein-based enzyme replacement therapy that patients typically take by two-hour infusions every two weeks.

Genzyme’s new capsule, called Cerdelga, can be taken twice a day by most patients, while a smaller group will take it once a day. It could treat many of the same patients who currently take Cerezyme for the most common form of Gaucher disease, an enzyme deficiency that can cause enlargement of the liver, excessive bleeding and bruising, and bone pain.

Cerdelga was approved by the Food and Drug Administration on Aug. 19 and will be launched in the United States this month by Genzyme, an arm of French drug maker Sanofi SA. In extensive clinical trials, the capsule relieved Gaucher disease systems by reducing fatty lipids produced by the body, allowing patients to live normally.

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The cost of Cerdelga is not unusual for rare disease drugs that qualify for tax credits and patent extensions under the federal Orphan Drug Act, which covers treatments for diseases afflicting fewer than 200,000 patients. Gaucher affects only about 2,000 people in the United States, some of whom are on medications from competing drug firms. It affects fewer than 10,000 people worldwide.

But the issue of drug prices has come under a spotlight this year as a driver of rising health costs. Payments for Sovaldi, a $1,000-a-day pill to treat hepatitis C, has strained the finances of health insurers. Sovaldi, sold by California-based Gilead Sciences, costs $84,000 for a three-month treatment regimen, and cures more than 90 percent of patients. Another high-profile pill, Tecfidera, sold by Biogen Idec Inc. of Cambridge, costs $60,121 a year to treat multiple sclerosis.

Unlike hepatitis C, which affects an estimated 3.2 million people in the United States, or multiple sclerosis, which affects more than 300,000, Gaucher disease’s small number of patients has made the aggregate cost of drugs such as Cerezyme less of a burden on insurance providers.

“Gaucher is among the rarest of the rare diseases,” said Genzyme spokeswoman Lori Gorski. “The health care system already has been taking care of people with Gaucher disease. This is not a new burden on the system. This gives patients and physicians the ability to choose the therapy that is best for their circumstances without consideration of the price.”

Spending on specialty pharmaceuticals — a class of drugs, including rare disease medicines, used to treat chronic or life-threatening conditions and typically high-priced — is projected to grow from $160 billion this year to $193 billion by 2017 in developed countries, according to the IMS Institute of Healthcare Informatics, a research group in Danbury, Conn. The institute cites the prices of drugs for cancer, diabetes, mental health, respiratory ailments, and pain as the fastest growing in the United States.

“It poses a challenge because a lot of these drugs are really breakthroughs and they’re drugs you want patients to have access to,” said Brendan Buck, vice president for America’s Health Insurance Plans, a trade group. “But they’re coming with increasingly high price tags that could become unsustainable for health plans, Medicaid, Medicare, and private businesses.”

In an interview last month, Genzyme president David Meeker said the company expected to price Cerdelga in the same range as Cerezyme.

“We are indifferent to whether patients take one drug or another,” he said. “We want to create a meaningful choice for patients and doctors.”

Gorski acknowledged the manufacturing cost of the Cerdelga pill is less than that of biotech drugs such as Cerezyme, which are produced through an organic process in giant vats called bioreactors. But she said other factors come into play in pricing a drug, such as development costs, the clinical value it brings to patients, and the rarity of the condition.

She also said the price was important to the “sustainability” of the drug maker “so Genzyme can continue to be here and innovate on behalf of unmet needs.”

Genzyme expects that many patients who use Cerezyme might gravitate to Cerdelga. But the new pill may also attract patients who take competing drugs marketed by Shire PLC of Lexington and a partnership of Pfizer Inc. and Israel’s Protalix BioTherapeutics.

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